The present invention relates to a process for producing a continuous alumina fiber blanket. More particularly, it relates to a process for producing a continuous alumina fiber blanket by subjecting an alumina fiber precursor formed from a spinning solution containing an aluminum compound to a heat treatment by using a specific high-temperature furnace.
Continuous blankets (continuous sheets) of alumina fiber are used, by vacuum molding them, as various types of heat-resisting materials, for example, heat insulator or joint filler of high-temperature furnaces or high-temperature ducts, and retainer of catalyst converter for cleaning exhaust gas from internal combustion engines. As the method of producing a continuous alumina fiber blanket, a process is known in which a continuous sheet of alumina fiber precursor formed from a spinning solution containing an aluminum compound is supplied continuously to a high-temperature furnace and subjected to a heat treatment therein while being carried in one direction by a carrying mechanism such as conveyor disposed in the said high-temperature furnace. (For example, European Patent Application Laid-Open No. 971057 (Japanese Patent Application Laid-Open (KOKAI) No. 2000-80547)).
However, in the above method, there is a possibility that the fibers in the blankets might be crushed or broken in the course of their production process, and there may arise such problems as non-uniformity of thickness or bulk density and insufficient strength of the product.